Plot S11 File with cursor attempt

plot_touchstone_with_cursor.py

# Create a Smith Chart and plot the contents of a .s1p file
import numpy as np
import skrf as rf
from matplotlib import rcParams, pyplot as plt
import sys
from mpl_smithchart import SmithAxes

# output settings
out_title = "Smith Chart Output"

# set the default filename
fname1 = 'test.s1p'

# check if there is any command line filename
if len(sys.argv) == 2:
    fname1 = sys.argv[1]


class SnappingCursor:
    """
    A cross-hair cursor that snaps to the data point of a line, which is
    closest to the *x* position of the cursor.

    For simplicity, this assumes that *x* values of the data are sorted.
    """
    def __init__(self, ax, line):
        self.ax = ax
        self.horizontal_line = ax.axhline(color='k', lw=0.8, ls='--')
        self.vertical_line = ax.axvline(color='k', lw=0.8, ls='--')
        self.x, self.y = line.get_data()
        self._last_index = None
        # text location in axes coords
        self.text = ax.text(0.72, 0.9, '', transform=ax.transAxes)

    def set_cross_hair_visible(self, visible):
        need_redraw = self.horizontal_line.get_visible() != visible
        self.horizontal_line.set_visible(visible)
        self.vertical_line.set_visible(visible)
        self.text.set_visible(visible)
        return need_redraw

    def on_mouse_move(self, event):
        if not event.inaxes:
            self._last_index = None
            need_redraw = self.set_cross_hair_visible(False)
            if need_redraw:
                self.ax.figure.canvas.draw()
        else:
            self.set_cross_hair_visible(True)
            x, y = event.xdata, event.ydata
            index = min(np.searchsorted(self.x, x), len(self.x) - 1)
            if index == self._last_index:
                return  # still on the same data point. Nothing to do.
            self._last_index = index
            x = self.x[index]
            y = self.y[index]
            # update the line positions
            self.horizontal_line.set_ydata([y])
            self.vertical_line.set_xdata([x])
            self.text.set_text(f'x={x:1.2f}, y={y:1.2f}')
            self.ax.figure.canvas.draw()




print(f'Opening file: {fname1}')

ntwk1 = rf.Network(fname1)
sdata = ntwk1.s
sdata = sdata.reshape(sdata.shape[0])

# customize the Smith Chart functionality here:
SmithAxes.update_scParams(grid_major_enable=True)

# create a figure and Smith Chart
fig = plt.figure(figsize=(10,10)).set_layout_engine('tight')
ax = plt.subplot(111, projection='smith')

# plot the data
line = plt.plot(sdata, markevery=5, label="trace1", datatype=SmithAxes.S_PARAMETER)

# final decorations
legend = plt.legend(loc="lower right", fontsize=12)
plt.title(out_title, fontsize=18)

# cursor
snap_cursor = SnappingCursor(ax, line)
fig.canvas.mpl_connect('motion_notify_event', snap_cursor.on_mouse_move)

# save the plot to a file
plt.savefig("export.png", format="png")

# display the plot
plt.show()